What is the format of Minecraft.net account names? Specifically, what characters are permitted or prohibited, what is the maximum length, and are they always treated as case-insensitive?
The username must be 16 characters or less.
The characters permitted are :
Usernames are case-sensitive in games (above your head), but when logging in using the username, whether is it in caps or not, will still work.
Trying to register with an illegal character gives an error and mentions the following as allowed:
And the longest username I could register was 'thisisalongusern'